I stumbled on this accidentally when I started to dial information (411) and meant to hang up with my finger before the last '1'. Instead, the switch hook "bounced" (making the click signifying the last '1') and I got connected anyway. (A bummer since every call to information was a charge on your bill.)

Still, once I figured that out my friends and I would try to call girls we liked using this method. The skill involved and the fact that you'd fail 2/3 of the time would distract you from the fear of actually talking to the girl once you got connected. "Oh, sh*t! It worked. Oh, hi, Rachel. I was playing around with the phone and must've accidentally dialed you."